Method for forming a bag

ABSTRACT

A method of forming a reclosable fastener track having a slider. The process provides a reclosable fastener track, forms a slit in the fastener track, attaches a slider to the fastener track, seals the slit in the fastener track after the slider attaches, and creates a first and a second end stop on the track.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. application Ser. No. 11/975,878filed on Oct. 22, 2007, which claims priority to U.S. ProvisionalApplication Ser. No. 60/854,751 filed on Oct. 27, 2006, each of which isincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a continuous process formaking slider reclosable fastener segments that may be applied to bags,including polymeric bags, and particularly to the method of installing aslider on the polymeric track of the reclosable fastener segment.

BACKGROUND OF THE INVENTION

Polymeric bags are popular household items that are used in a variety ofapplications including storage of food. The addition of reclosablefastener tracks or zippers to these bags has further enhanced theirutility and the addition of a slider has made the fasteners easier toopen and close. The fasteners include complementary first and secondprofiles that engage each other to close the bag. Previous methods ofattaching a slider to the reclosable fastener track have often involvedattaching a slider to a reclosable fastener track already attached to apolymeric bag, or web of film. An example of such a prior attempt isdescribed in U.S. Pat. No. 5,431,760 to Donovan. However, it would bebeneficial to attach a slider to a reclosable fastener track that is notalready attached to a polymeric bag, or web of film. A need thereforeexists for a method of attaching a slider to a reclosable fastener trackin a continuous process prior to attaching the reclosable fastener trackto a polymeric film or bag that is accomplished in an efficient and costeffective manner.

SUMMARY OF THE INVENTION

According to one process, a method of forming a reclosable fastenertrack having a slider is provided. The method provides a reclosablefastener track, forms a slit in the track, attaches a slider to thetrack, seals the slit, and creates a first and a second end stop on thetrack. The track has a first fin portion and a second fin portion. Thefirst fin portion has a first profile, while the second fin portion hasa second profile. The first and the second profile cooperate to form areclosable seal. The slit forms through the profiles of the track andportions of the fins nearest to the profiles. The slider is attachedover the slit in the track.

According to another process, a method of forming a reclosable fastenertrack having a slider is provided. The method provides a reclosablefastener track, forms a slit in the track, attaches a slider to thetrack, and seals the slit. The track has a first fin portion and asecond fin portion. The first fin portion has a first profile, while thesecond fin portion has a second profile. The first and the secondprofile cooperate to form a reclosable seal. The slit forms through theprofiles of the track and portions of the fins nearest to the profiles.The slider is attached over the slit in the track.

According to a further process, a method of forming a bag with areclosable fastener track having a slider is provided. The methodprovides a reclosable fastener track, forms a slit in the track,attaches a slider to the track, seals the slit, creates a first and asecond end stop on the track, attaches the fastener track to a film orbag, and forms a bag from the film. The track has a first fin portionand a second fin portion. The first fin portion has a first profile,while the second fin portion has a second profile. The first and thesecond profile cooperate to form a reclosable seal. The slit formsthrough the profiles of the track and portions of the fins nearest tothe profiles. The slider is attached over the slit in the track.

According to yet another process, a method of forming, filling andsealing a bag with a reclosable fastener track having a slider isprovided. The method provides a reclosable fastener track, forms a slitin the track, attaches a slider to the track, seals the slit, creates afirst and a second end stop on the track, attaches the fastener track toa film or a bag after the slider attaches, forms a bag from the film,adds a product to the bag and seals the bag. The track has a first finportion and a second fin portion. The first fin portion has a firstprofile, while the second fin portion has a second profile. The firstand the second profile cooperate to form a reclosable seal. The slitforms through the profiles of the track and portions of the fins nearestto the profiles. The slider is attached over the slit in the track.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a system adapted to place a slider on areclosable fastener track according to one embodiment.

FIG. 2 is an enlarged perspective view of an area of the reclosablefastener track after the slider has been attached and end stops havebeen formed on the track.

FIGS. 3 a-3 c are enlarged views of the application of the slider to thetrack according to one embodiment.

FIG. 4 is a top view of a horn used in the ultrasonic welding process ofthe system shown in FIG. 1.

FIG. 5 is a side view of an anvil used in an ultrasonic welding processof the system shown in FIG. 1.

FIG. 6 is a front side view of a polymeric bag having a reclosablefastener track and slider.

FIG. 7 is an enlarged view of a first end of the reclosable fastenertrack and slider of the bag of FIG. 6.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed but, on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIG. 1, there is illustrated a system 10 adaptedto carry out one process to apply a slider 12 to a continuous reclosablefastener track 14. In one embodiment, the track 14 includes a firstprofile and a second profile. Each of the first and second profiles 15a, 15 b (FIG. 3 a) includes a respective fin 15 c, 15 d (FIG. 3 a)extending generally downwardly therefrom.

It is contemplated that the first and second fin portion may be attachedto form a tamper-evident closure. As shown in FIG. 3 b, a tamper-evidentseal 34 is formed between the first fin 15 c and the second fin 15 d.The profiles and fin portions may be attached in other methods to form atamper-evident closure. One example of a tamper-evident closure is aone-time breakable preferential area of weakness. To form the one-timebreakable preferential area of weakness or preferential tear area, thelower edges of the first and second fin portions 15 c, 15 d are joinedto each other along a one-time breakable preferential area of weaknessor preferential tear area to form a one-time openable tamper evidentfeature. The joined first and second fin portions have a generallyU-shaped or V-shaped cross-sectional configuration. Other embodiments ofthe fastener 14 may not include the tamper evident feature leaving thefin portions disconnected. It is contemplated that other tamper-evidentembodiments may be formed.

The first and the second profile of the track 14 have complementarycross-sectional shapes that are adapted to interact to form a reclosableseal on the track 14. The first and the second fin portions are adaptedto attach the track 14 to a polymeric bag, or web of film, as will bedescribed in greater detail below in reference to FIG. 6. It is to beunderstood that the present invention is not limited to any particularshape of a first and a second profile for the track 14, but rather anyprofiles that allow a reclosable seal to be formed on the track 14 arecontemplated by the present invention. It is also to be understood thatthe present invention is not limited to any particular slider shape.

A spool 16 of reclosable fastener track 14 is provided according to oneprocess. It is contemplated that the fastener track 14 may be stored anddelivered in other manners. The track 14 is fed from the spool 16through low-tension rollers 18 of the system 10 to alleviate the amountof tension in the track 14. The continuous length of fastener track 14next has a slit 22 formed through the first and second profile portionsas well as an area of each of the fin portions nearest the first andsecond profiles of the track 14 by a knife 20 or other cutting device.It is contemplated that the knife 20 may be formed of differentmaterials. In one embodiment, the knife is nitride coated. The knife 20is adapted to form the slit 22 at an angle of from about thirty degrees(30°) to about one hundred and fifty degrees (150°) relative to themotion of travel of the track 14. In another embodiment, the slit may beformed by a cutting device at an angle of from about 30° to about 120°or more desirably from about 450 to about 90° relative to the motion ofthe travel of the track 14. Providing the knife 20 or other cuttingdevice with a forty-five degree (450) angle relative to the direction ofmotion of the track 14 has been found to be most effective for anultrasonic-welding portion of the process. Providing the knife 20 orother cutting device with a ninety degree (900) angle relative to themotion of the track 14 has been found to be most effective for placingthe slider 12 on the track.

Once the slit 22 has been formed in the reclosable fastener track 14, aslider 12 is applied to the track 14. The slider 12 is slidably mountedto the fastener track 14 for movement between a closed position and anopen position. The first and second profiles 15 a, 15 b (FIG. 3 a) areengaged to each other while the slider 12 is in the closed position. Thefirst and second profiles 15 a, 15 b (FIG. 3 a) are disengaged from eachother in response to movement of the slider 12 from the closed positionto the open position. One non-limiting example of fastener and sliderarrangement is disclosed in U.S. Pat. No. 5,067,208 to Herrington, Jr.et. al.

In one process, the slider 12 is applied using a pusher 24 that places alateral force on the slider 12 as the track 14 moves past the pusher 24.Turning to FIG. 3 a, the pusher 24 applies a force to the slider 12 in adirection that is generally normal to the direction the reclosablefastener track 14 is moving. As shown in FIG. 3 b, the force applied bythe pusher 24 on the slider 12 causes a “leading edge” of the track 14to displace slightly as the pusher 24 presses on the slider until a backstop 25 is reached. As shown in FIGS. 3 b and 3 c, when the slit 22reaches the slider 12 and the pusher 24, the “trailing edge” portion ofthe track 14 nearest the slit 22 enters the slider 12 as the profileportions of the “leading edge” of the track 14 displace from the lateralforce applied by the pusher 24. Once both the first and the secondprofiles of the track 14 have fully entered the slider 12, the pusher 24may be withdrawn, and the slider 12 moves along with the reclosabletrack 14. At this stage of the process, the slider 12 is fullyfunctional to facilitate the opening and the closing of the reclosabletrack; however, the slider 12 is not constrained to the track 14, andmay be removed from the track if the slider 12 moves past one of theslits 22 formed on the track 14.

The pusher 24 may be actuated using pneumatics, hydraulics, a servomotor, electrical solenoid, manually operated, or by other knownmethods. It is contemplated that the slider may be attached over theslit using methods other than those involving a pusher.

Next, referring back to FIG. 1, the continuous length of reclosabletrack 14 with the slider 12 attached enters an ultrasonic-welding area26. Prior to entering the ultrasonic-welding area 26, the reclosabletrack 14 contains alternating sliders 12 and slits 22, such that eachslider 12 is located between two adjacent slits 22. Within theultrasonic welding area 26, the slit 22 is resealed and end stops or endterminations 48, 52 (FIG. 2) are formed on the track 14. It iscontemplated that the end stops may be separate components that areadded to the track. The ultrasonic welding area 26 includes a horn 28and an anvil 30 (FIG. 5). The horn 28 is located on a first side of thetrack 14 while the anvil 30 is located on the opposite side of the track14 as the horn 28. The horn 28 emits ultrasonic energy that melts thepolymeric material of the track 14 to reseal the slit 22 and form theend stops 48, 52. It is advantageous to reseal the slit 22 to preventthe slit 22 from catching on other equipment used in additionalprocessing, or from allowing portions of the track 14 near the slit tobreak off and fall into contents, if any, that are later added to a bagthat has the attached track. It is further advantageous to reseal theslit 22 to allow additional tension to be placed on the track 14 withoutlosing structural integrity of the track 14.

Turning to FIG. 4, the horn 28 is shown in greater detail. The horn 28has three areas, a first end stop area 36, a slit resealing area 38, anda second end stop area 40. The first and second end stop areas 36, 40project farther towards the reclosable track 14 than the slit resealingarea 38.

As shown in FIG. 5, the anvil 30 of the ultrasonic welding area 26 has afirst end stop area 42, a slit resealing area 44, and a second end stoparea 46. The slit resealing area 44 has about a 0.020 inch gap at both atop and a bottom of the resealing area 44 relative to the height of thefirst and second end stop areas 42, 46. This 0.020 inch gap acts as adam to constrain a sufficient amount of melted polymeric material toreseal the slit 22 completely. It is contemplated that the gap may varyin size. It is contemplated that other methods may be used to form anend stop and reseal the slit.

Turning to FIG. 2, the reclosable track 14 is shown after the ultrasonicwelding has been performed. Following the ultrasonic welding, the track14 has a first end stop 48, a resealed slit area 50, and a second endstop 52. The second end stop 52 shown in FIG. 2 is part of a leadingreclosable track segment, while the first end stop 48 is part of atrailing reclosable track segment. Thus, the ultrasonic-welding area 26operates on two segments of reclosable track at one time, the trailingedge of a first segment, and the leading edge of a second segment. Theresealed slit area 50 is generally located between the first and thesecond reclosable track segment. Once the first and the second end stops48, 52 of a given segment of reclosable track are formed the slider 12is fully retained on the track segment.

Referring again to FIG. 1, after the ultrasonic welding is complete, thereclosable track 14 includes a fully retained slider 12. The reclosabletrack 14 with the slider 12 attached may then be rolled onto a spool forlater use, or may be further processed. For example, the continuousreclosable track 14 with the slider 12 may be cut into individualsegments that have a length of about the distance between the end stops48, 52 on one segment of the track 14. The individual segments may becut using knives (not shown) just past the nip rollers 56 a, 56 b. Thenip rollers 56 a, 56 b providing a force to the track 14 that causes thetrack 14 to move. The nip rollers 56 a, 56 b are not required if thetrack 14 is being fed directly into a bag-forming device 54, as thebag-forming device 54 will provide a force necessary to move the track14. Further, the reclosable track 14 with the slider 12 may also be fedinto a device 54 for forming polymeric bags, such as a vertical form,fill, and seal device, or a horizontal form, fill, and seal device, orany other bag-making device. In vertical and horizontal form, fill, andseal processes, further processing steps may occur after attaching theslider and fastener to the film that eventually forms a bag. Product isthen added to the film or bag. It is contemplated that the bag may beinterconnected, or a separate bag. It is contemplated that the attachedslider and fastener may be added to form a pre-made fastener bag.

One advantage of the system 10 is the ability to produce individualsegments of reclosable track 14 with a slider 12 attached, while thetrack 14 is not attached to a bag. Therefore, track segments may be usedon a wide variety of machine types, or even hand sealing operations, atan end user's facilities for attaching the track segments to bags or aweb of film.

Another advantage of the system 10 is the speed of operation. The system10 is capable of operating at speeds up to 200 cycles per minute, whilemany previous machines may only apply sliders at speeds of up to 130cycles per minute. Utilizing ultrasonic welding to form the end stops48, 52 typically reduces the operating speed of the system 10 below the200 cycles per minute that the system 10 is capable of applying sliders12 to the track 14.

Turning next to FIG. 6, a polymeric bag 100 having a segment ofreclosable track 114 with a slider 112 is shown. The bag 100 includes apair of opposing wall panels that make up a package body and define areceptacle space for products. The opposing wall panels may comprisepolymeric film, multilayer and multi-component laminations orcoextrusions. The bag 100 is a hooded bag, in that it has an area 102above the reclosable track 114. The reclosable track is attached to thebag 100 along fin portions 116 of the reclosable track 114. The finportion 116 attaches to the bag 100 via conventional methods, such as,for example, a heat-sealing process. The fin portions 116 of thereclosable track 114 are made of a barrier material that prevents orinhibits air from entering the bag 100. The bag 100 may be formed via ahorizontal form, fill, and seal process, a vertical form, fill, and sealprocess, or any other bag-forming process known in the art. Supplying asegment of reclosable track affords a user a great deal of flexibilityin the bag-forming process.

Different products may be added in a form, fill and seal operations. Forexample, nuts, candy, snacks, salt, cheese, other food and non-foodproducts may be packed in these packages by form, fill and seal machinesand sold to consumers.

The bag 100 may be formed by folding a web of material, such aspolymeric film, multilayer and multi-component laminations orcoextrusions consisting of polymer, paper, metalized polymer or foil inany combination. The folded web forms the package body and defines thereceptacle space bounded by the opposing wall panels and a packagebottom. After the fastener 14 with slider 12 is attached to the wallpanel, a vertical seal bar joins the wall panels together to form a sideseal at defines a side wall of the reclosable package. The distancebetween adjacent side seals should be approximately equal to the desiredwidth of the reclosable package. The side seal may be formed by heatseal, adhesive or any other appropriate method to form a strongpreferably hermetic seal. The product may directed into the package by afunnel.

After the product fills the package, a second top seal bar adheres thefastener 14 to the other wall panel preferably hermetically sealing theproduct within the package. The second top seal bar moves back and forthto provide a second top seal that adheres the second track to the wallpanel. The second top seal between the wall panel and second track. Thefastener may be adhered to the wall panels of the web by heat seal,adhesive or any other appropriate method to form a strong preferablyhermetic second top seal. To divide the adjacent packages of productthat are connected by the side seal in one process, a knife cuts theside seal such that the side walls of each package remain secure. It iscontemplated that the fastener 14 may be attached to a formed baginstead of an interconnected bag.

In another embodiment of the form, fill and seal process, a side sealmay be cut before filling the package with the product. In thisembodiment, the process folds the web and positions and top seals thefastener 14 to one of the wall panels. Next, the process forms and cutsthe side seals. After the knife cuts the side seals, the product fillsthe package and the second top seal closes the package. In anotherembodiment of the form, fill and seal process, the fastener may besealed to one of the wall panels prior to the folding of the web.

According to another process, end stops on individual track segments maybe formed by a process other than ultrasonic-welding, such as, forexample, a heat-sealing process.

While the present invention has been described with reference to one ormore particular embodiments, those skilled in the art will recognizethat many changes may be made thereto without departing from the spiritand scope of the present invention. Each of these embodiments andobvious variations thereof is contemplated as falling within the spiritand scope of the claimed invention, which is set forth in the followingclaims.

1. A method of forming a bag, the method comprising the acts of:providing a reclosable fastener track, the track having a first finportion and a second fin portion, the first fin portion having a firstprofile and the second fin portion having a second profile, the firstand the second profiles cooperating to form a reclosable seal; forming aslit in the track, the slit being formed through the profiles of thetrack and portions of the fins nearest the profiles; attaching a sliderto the track, the slider attaching over the slit in the track; sealingthe slit in the track creating a resealed area; creating a first endstop and a second end stop on the track; attaching the fastener track toa film or the bag after the act of attaching the slider to the track;and forming the bag from the film.
 2. The method of claim 1 wherein thefastener track is attached to the bag.
 3. The method of claim 1 whereinthe fastener track is attached to the film.
 4. The method of claim 1wherein the first and second end stops are created at or near theresealed area.
 5. The method of claim 1, wherein the act of creating thefirst end stop and the second end stop utilizes ultrasonic-welding. 6.The method of claim 5, wherein the sealing the slit is performedutilizing ultrasonic welding and the acts of sealing the slit in thetrack and creating the first end stop and the second end stop areperformed using a single ultrasonic-welding process.
 7. The method ofclaim 1, wherein the act of attaching the slider to the track includesutilizing a pusher that holds the slider and applies a lateral force onthe track, the lateral force displacing the track as the slit approachesthe holder allowing the slider to attach to the track.
 8. The method ofclaim 1, wherein the act of forming the slit includes forming the slitat an angle of at from about a thirty degrees to about a ninety degreesrelative to the direction of motion of the reclosable fastener track. 9.The method of claim 8, wherein the act of forming the slit forms theslit at an angle of about thirty-five degrees to an angle of aboutfifty-five degrees relative to the direction of travel of the reclosablefastener track.
 10. The method of claim 1 further comprising the act ofcutting the fastener track at about the location of the resealed areaproviding segments of reclosable fastener track having a slider, a firstend stop, and a second end stop before the act of attaching the fastenertrack to a film or a bag.
 11. A method of forming a bag, the methodcomprising the acts of: providing a reclosable fastener track, the trackhaving a first fin portion and a second fin portion, the first finportion having a first profile and the second fin portion having asecond profile, the first and the second profiles cooperating to form areclosable seal; forming a slit in the track, the slit being formedthrough the profiles of the track and portions of the fins nearest theprofiles; attaching a slider to the track, the slider attaching over theslit in the track; sealing the slit in the track creating a resealedarea; attaching the fastener track to a film or the bag after the act ofattaching the slider to the track; and forming the bag from the film.12. The method of claim 11 wherein the fastener track is attached to thebag.
 13. The method of claim 11 wherein the fastener track is attachedto the film.
 14. The method of claim 11, wherein the act of forming theslit includes forming the slit at an angle of at from about a thirtydegrees to about a ninety degrees relative to the direction of motion ofthe reclosable fastener track.
 15. The method of claim 15, wherein theact of forming the slit forms the slit at an angle of about thirty-fivedegrees to an angle of about fifty-five degrees relative to thedirection of travel of the reclosable fastener track.
 16. The method ofclaim 11 further comprising the act of cutting the fastener track atabout the location of the resealed area providing segments of reclosablefastener track having a slider, a first end stop, and a second end stopbefore the act of attaching the fastener track to a film or a bag.
 17. Amethod of forming, filling and sealing a bag, the method comprising theacts of: providing a reclosable fastener track, the track having a firstfin portion and a second fin portion, the first fin portion having afirst profile and the second fin portion having a second profile, thefirst and the second profiles cooperating to form a reclosable seal;forming a slit in the track, the slit being formed through the profilesof the track and portions of the fins nearest the profiles; attaching aslider to the track, the slider attaching over the slit in the track;sealing the slit in the track creating a resealed area; creating a firstend stop and a second end stop on the track; attaching the fastenertrack to a film or the bag after the act of attaching the slider to thetrack; forming the bag from the film; adding product to the bag; andsealing the bag.
 18. The method of claim 17 wherein the fastener trackis attached to the bag.
 19. The method of claim 17 wherein the fastenertrack is attached to the film.
 20. The method of claim 17 wherein thefirst and second end stops are created at or near the resealed area.